The US Federal Bureau of Investigation (FBI) is reportedly investigating the possibility that a number of US banks have become the recent victims of cyberattack.

On Wednesday, multiple news outlets reported that Russian hackers may have carried out cyberattacks against JPMorgan Chase and another US bank earlier this month. The New York Times reported that JPMorgan Chase and at least four other US banks were targeted in a string of coordinated attacks over the course of this month.

Bloomberg says that law enforcement agencies are investigating whether the cyberattacks are related to recent attacks on European banks.

"We are working with the United States Secret Service to determine the scope of recently reported cyber attacks against several American financial institutions."

The spokesman declined to name the banks in question, but according to Reuters sources, JPMorgan Chase is one of the US financial institutions affected. The financial institution is still conducting its own internal investigation to determine what occurred.

JPMorgan spokesman Brian Marchiony declined to discuss the specific cyberattack, but told the publication that "companies of our size unfortunately experience cyber attacks nearly every day. We have multiple, layers of defense to counteract any threats and constantly monitor fraud levels."

According to the Wall Street Journal, up to five banks may have been affected. WSJ sources say that the investigation so far has revealed that hackers were able to make significant strides in infiltrating JPMorgan's systems, and large quantities of data were stolen, including checking and savings account data.

The cyberattack is believed to have stemmed from an employee's personal computer, which was infected with malware that provided a VPN tunnel into the bank's networks.

Sources close to the investigation say it is too early to determine which country the attack originated from, or who may be responsible.

If true, this is not the first time JPMorgan has been a target of cyberattack. In December, the bank admitted to a security breach which left 465,000 prepaid cash card customer records at risk.